1. Field of the Invention
The present invention relates to an IC socket for use in testing the performance of a semiconductor package device, and particularly to an IC socket provided with a positioning guidance structure for reliably guiding the ball bumps, which are the external terminals, of a BGA (Ball Grid Array) package to the contact pins (C/P) of an IC socket.
2. Description of the Related Art
The IC socket for a BGA package according to the prior art shown in FIG. 1 is made up of IC socket body 3 which is formed in a single block so as to have at least two mutually opposing parallel surfaces. A plurality of contact pins (C/P) 4 are embedded in this IC socket body 3 perpendicular with respect to the two mutually opposing parallel surfaces of IC socket body 3. The plurality of contact pins (C/P) 4 are arranged so as to match the positions of the ball bumps (for example, solder balls) of BGA package 1. The tip of each contact pin 4 protrudes from one of the two mutually opposing parallel surfaces of IC socket body 3. This surface is hollowed out in a bowl-shaped form at the periphery of the tip of each contact pin 4 as guide depressions 5 for ball bumps 2. In addition, the tip portion of each contact pin 4 is pressed toward the outside by a spring (not shown) inserted inside each contact pin 4. When pressed from the outside against the resilience of the springs, the tips of the contact pins 4 consequently recede into the interior of the IC socket body 3.
If the ball bumps 2 are properly aligned with the tips of the contact pins 4 in such an IC socket, the position of bumps 2 can be secured at the tips of contact pins 4 by the guide depressions 5 when the bumps 2 are pressed against the tips of contact pins 4, as shown in FIG. 2.
However, an IC socket according to the foregoing description is constructed such that the tips of contact pins 4 protrude beyond guide depressions 5, and as a result, at the time of contact, the bumps 2 of BGA package 1 come into contact with the tips of contact pins 4 before guide depressions 5 of the IC socket. Accordingly, in a case in which the centers of bumps 2 diverge from the outside (D) of contact pins 4 as shown in FIG. 3, position correction by guide depressions 5 of the IC socket is complicated and contact failures result.